when marking more than one mail and deleting them, they dont move to trash

[alexboy]

they are deleted, but not in trash.
one single message ist ok, but marking a couple and click 'delete' the trash isnt filled with them.

[alexboy]

this error only happens if i mark the mails like this:

click on the first, hold shift and click the last one.
then click delete. the messages are deleted, but not in the trash.

if i click 'mark all' and click delete, it works.